Steel alloy



Patented Oct. 30, 1934 1,979,015 PATENT OFFICE STEEL'ALLOY Ernst Hermann Schulz, Dortmund, Germany, as-

signor to Vereinigte Stahlwerke schaft, Dusseldorf, Germany Aktiengcsell- No Drawing. Application January 28, 1932, Serial German No. 589,525. In

Claims.

This invention relates to a process for. obviating or reducing cold shortncl inatee'ls containing phosphorus.

a It is a known fact that as the phosphorus conv 5 tent in steels increases the tendency to cold shortness also increases, which is particularly evident in the scrap from the notched-bar toughness tests. Thus, according to Oberhoiler Das technische Eisen 1925, Springer, Berlin, phosphorus is classed as an undesirable element from the pointof view of iron foundry work having regard to its undeniable action as a producer of cold shortness. Soft ingot steel is definitely brittle even when containing about 0.10% 01'' 5 phosphorus and-when said steelcontains more than 0.15% phosphorus, the measured value for the notched-bar toughness is so small as to render the steel useless for practical purposes.

It has unexpectedly been shown in accordance with the present invention that the addition of chromium (which otherwise exerts a hardening eilect and therefore reduces rather than increases the toughness of the steel) will reduce to a great extent or entirely obviate the brittleness produced by the phosphorus.

Therefore the invention consists in a steel, containing between about 0.05 and 0.30% of car-,

ban and a raised phosphorus content above 0.08% and for reducing the brittleness caused by the raised phosphorus content in addition thereto between about 0.25 and 1.5%, preferably 0.5 to

-1% of chromium. The phosphorus content of the steel according to the invention lies preferably between about 0.08'and 0.17% and may be increased with increasing chromium content, so

that with consequent increase of chromium content it may reach the highest amount of about 0.3% of phosphorus which is to be found in malleable iron.-

The examples'given hereinafter. relating to a steel containing about 0.10% of carbon clearly show the effects ofthe influence of chromium. The specific impact test (notched-bar toughness) is selected as a criterion for the toughness or brittleness together with the behavior of the test pieces under the impact test, such as is prescribed by the German State Railway Company for rail steels.

y December 15, 1930 It is readily apparent from these examples, that in the case of steels with phosphorus contents in which ordinarily the notched-bar toughness is reduced to quite negligible proportions and in which the rail impact test.does not satisfy the prescribed conditions, the notched-bar toughness can by the addition of chromium be increased to a value which is a multiple of that of the steel without chromium and the impact test can be made to satisfy the prescribed requirements by the addition of chromium to said steel.

It is possible to bring, out this effect produced by the chromium content to a more pronounced degree the lower the carbon of the steel and the lower the inherent brittleness thereof, the 75 process being primarily applicable to steels containing up to about 0.3% of carbon. In this connection it is an advantage to increase the chromium .content as the phosphorus content increases.

I claim:--

1. A steel'alloy containing between about 0.05 and 0.3% of carbon and between about 0.5 and 0.75% of chromium for reducing the brittleness caused by a phosphorus content between about 0.08 and 0.17%, the balance of the alloy consisting substantially of iron.

2. A steel alloy containing between about 0.05 and 0.3% of carbon and between about 0.25 and 1.5% of chromium for reducingfthe brittleness caused by a phosphorus content-betweenabout 0.08 and 0.17 the balance ofthe alloy consisting substantially of iron. v I v 3. A steel alloy containing between about 0.05 and 0.3% of carbon and between about 0.5 and 0.75% of chromium for reducing the brittleness caused by a phosphorus content between about 0.08 and 0.3%, the balance of the alloy consisting substantially of iron.

4. A steel alloy containing between about 0.05 and 0.3% of carbon and between about 0.25 and 1.5% of chromium for reducing the brittleness caused by a phosphorus content between about 0.08 and 0.3%, the balance of the alloy consisting substantially of iron.

5. A steel alloy containing between about 0.05 and 0.3% of carbon and between about 0.5 and 0.75% of chromium for reducing the brittleness caused by a phosphorus content between about 0.08 and 0.17%, the balance of the alloy consisting substantially of iron, the chromium content being increased as the phosphorus content increases. ERNST HERMANN SCHULZ. 

